Create a Custom Hyperlink Field for Item's Web Store Link

1. Navigate to Customization > Lists, Records, & Fields > Item Fields > New.
2. Enter a name in the Label field.
3. Set the Type to Hyperlink.
4. Uncheck the Store Value field.
5. Check the check boxes of the item types in which the field should be added on the Applies To tab.
6. Click the Validation & Defaulting tab.
7. Set the Default Value to the formula below:

CONCAT(CONCAT('http://shopping.netsuite.com/s.nl/c.TSTDRVxxxxxx/it.A/id.',{internalid}), '/.f')

Note: Replace the TSTDRVxxxxxx part of the formula with the NetSuite Account ID and replace {internalid} with the item internal ID.

8. Save.